Active matrix substrate method of manufacturing active matrix substrate, and display device

Abstract

Provided is an active matrix substrate that includes a substrate, a thin film transistor, an electrode layer, and a second insulating film. The thin film transistor is provided on the substrate and includes an oxide semiconductor layer, a gate electrode, and source and drain electrodes. The oxide semiconductor layer includes a first region as a channel region. The electrode layer is level with the gate electrode, is provided in a different region from the thin film transistor, and includes a first end. The second insulating film is provided between the substrate and the electrode layer and includes a second end at a more retreated position than the first end of the electrode layer. The oxide semiconductor layer further includes a second region having lower resistance than the first region. The electrode layer is electrically coupled, at the first end, to the second region of the oxide semiconductor layer.

What is claimed is: 
     
       1. An active matrix substrate, comprising:
 a substrate; 
 a thin film transistor that is provided on the substrate and includes an oxide semiconductor layer, a gate electrode, and source and drain electrodes, the oxide semiconductor layer including a first region as a channel region, the gate electrode being disposed in confronted relation with the first region of the oxide semiconductor layer with a first insulating film in between, and the source and drain electrodes being electrically coupled to the oxide semiconductor layer; 
 an electrode layer in a different region from the thin film transistor, and includes a first end adjacent to the thin film transistor; and 
 a second insulating film that is provided between the substrate and the electrode layer and includes a second end adjacent to the thin film transistor, wherein the second end is farther from the thin film transistor than the first end of the electrode layer, 
 the oxide semiconductor layer further including a second region having lower resistance than the first region, and 
 
       the electrode layer being electrically coupled, at the first end, to the second region of the oxide semiconductor layer, wherein
 the electrode layer directly contacts both a top surface of the second insulating film and a side surface of the second insulating film. 
 
     
     
       2. An active matrix substrate, comprising:
 a substrate; 
 a thin film transistor that is provided on the substrate and includes an oxide semiconductor layer, a gate electrode, and source and drain electrodes, the oxide semiconductor layer including a first region as a channel region, the gate electrode being disposed in confronted relation with the first region of the oxide semiconductor layer with a first insulating film in between, and the source and drain electrodes being electrically coupled to the oxide semiconductor layer; 
 an electrode layer in a different region from the thin film transistor, and includes a first end adjacent to the thin film transistor; and 
 a second insulating film that is provided between the substrate and the electrode layer and includes a second end adjacent to the thin film transistor, wherein the second end is farther from the thin film transistor than the first end of the electrode layer, 
 the oxide semiconductor layer further including a second region having lower resistance than the first region, and 
 the electrode layer being electrically coupled, at the first end, to the second region of the oxide semiconductor layer, wherein 
 a bottom-most surface of the electrode layer is closer to the substrate than a top-most surface of the second insulating film. 
 
     
     
       3. An active matrix substrate, comprising:
 a substrate; 
 a thin film transistor that is provided on the substrate and includes an oxide semiconductor layer, a gate electrode, and source and drain electrodes, the oxide semiconductor layer including a first region as a channel region, the gate electrode being disposed in confronted relation with the first region of the oxide semiconductor layer with a first insulating film in between, and the source and drain electrodes being electrically coupled to the oxide semiconductor layer; 
 an electrode layer in a different region from the thin film transistor, and includes a first end adjacent to the thin film transistor; and 
 a second insulating film that is provided between the substrate and the electrode layer and includes a second end adjacent to the thin film transistor, wherein the second end is farther from the thin film transistor than the first end of the electrode layer, 
 the oxide semiconductor layer further including a second region having lower resistance than the first region, and 
 the electrode layer being electrically coupled, at the first end, to the second region of the oxide semiconductor layer, wherein 
 the electrode layer directly contacts the second region.